Solid insulated breaker of a small size

ABSTRACT

A solid state material insulated breaker of a small size comprising a molded main cylinder of electrically insulating material. The main cylinder is sealed at the upper and lower ends thereof and encloses a breaker unit having a fixed and a movable contacts therein. An insulating material is enclosed in said insulating cylinder. Two electrical conductors covered with a solid state insulating material are inserted respectively through two longitudinally spaced holes in the wall of said insulating cylinder, and connected electrically to said fixed and movable contacts.

Himi

1111 3,855,435 1451 Dec. 17, 1974 [75] Inventor:

1 1 SOLID INSULATED BREAKER A SMALL SIZE Hitoshi Himi, Tokyo, Japan [73]Assignee: Kabushiki Kaisha Meidensha,

Tokyo, Japan [22] Filed: Oct. 30, 1973 [21] Appl. No.: 411,068

[30] Foreign Application Priority Data Nov. 1, 1972 52 us. c1. 200/144B, ZOO/148 o, 200/150 R 51. 1111. C1. Hlh 33/66 58 Field of Search200/14 B, 1480, 148 R,

Japan 47-109670 3,471,669 /1969 Curtis ZOO/144B 3,571,543 3/1971 Perkinset a1. ZOO/144 B 3,751,617 8/1973 Bohlinger 200/144 B PrimaryExaminerRobert S. Macon Attorney, Agent, or Firm-Waters, Roditi,Schwartz &

Nissen 57] ABSTRACT A solid state material insulated breaker of a smallsize comprising a molded main cylinder of electrically insulatingmaterial. The main cylinder is sealed at the upper and lower endsthereof and encloses a breaker unit having a fixed and a movablecontacts therein. An

insulating material is enclosed in said insulating cylinder. Twoelectrical conductors covered with a solid ZOO/150 R I state insulatingmaterial are inserted respectively [561 Cite I i231 15.2511315251132 3 ZZSZEJLEZZ leilfillfl' fi UNITED STATES PATENTS said fixed and movablecontacts. 7 3,123,698 3/1964 Waterton 200/148 G r 3,147,356 9/1964Luehring '200/144 B Claims, 6 Drawing Figures as M b l sour) INSULATEDBREAKER or A SMALL srzr:

BACKGROUND OF THE INVENTION This invention relates to an electricbreaker and more particularly to a solid insulated breaker orinterrupter of a small size.

Recently, in the great towns, with the growth in population and theexcessive density of the building and the industrial institutions, theneed for the electric power has rapidly increased, but it is always verydifficult to reserve the site of the transformer substation in thedensely aggregated areas of the great towns. Accordingly, efforts aredirected to reduce the site as well as the equipments of the transformersubstation. Correspondingly, a breaker of a small size is also required,thus the insulated breaker has been manufactured in a small size insteadof using air insulation requiring the long insulation distance, but byusing the solid, liquid or gas insulation between the electricconductive parts and the grounded member to shorten the insulationdistance.

A breaker for a small sized transformer substitution accordingto one ofthe above insulation methods, for example, of 7.2 K V or 24 KVclassaccording to the solid state insulation has been manufactured bydisposing inside the mold its live conductive parts such as lead wires,breaker unit and the like, injecting a molten electric insulationmaterial composed mainly of the epoxy resin into the space between themold and the live conductive parts including the breaker unit, andforming all the parts in one molded body.

In this case, even if the breakers for the small-sized transformersubstation may be at equal ratings, various mold types must be preparedaccording to thefitting conditions of the breakers (for example, thefitting dimensions of the breaker to the face of the powerboard) or theusing conditions (in'th'e open air or in a house). Namely, when theexterior form of the breaker for the small-sized transformer changesaccording to tively large scale production of the breaker at one andthesame electric rating is required, the adequate returns will be broughtto some extent. But whenthe circuit for the breaker is of highorultra-high voltage, the breaker for the small-sized transformersubstation according to the solid material insulation method isgenerally not requested in large quantities, and further as the moldedproduct becomes of large size and of a complex structure, the moldtherefor is very costly'and does not pay in a financial view point.

OBJECTS AND SUMMARY OF THE INVENTION Accordingly, the object of thepresent invention is to solve the above problems and to provide asmall-sized and solid material insulated breaker or interrupter for ahigh voltage which can be manufactured at moderate costs withoutneeding" any costly molding.

Another object of the present invention is to provide a small-sized andsolid material insulated breaker which can be used for the transformersubstation of a small size and variously manufactured at moderate costsin small quantities.

A.further object of the present invention is to provide a small-sizedbreaker which can be manufactured as a breaker with a housing of adesired dimension easily and in a comparatively short time.

In brief, a small-sized breaker according to the pres ent inventionincludes a main cylinder of electrically insulating solid materialsealed at the upper and lower ends thereof and having a breaker unitenclosed therein, said breaker unit including fixed and movable contactmembers, two elongated insulated electric conductors passing through thewall of the main cylinder at longitudinally distant positions thereon,said conductors being at one ends connected to the fixed and movablecontact members of the breaker and atthe other ends adapted to' contactthe ends of bus-bars, and an electrically insulating material filled up'between said breaker unit and said main cylinder. 7

The small-sized and solid material insulated breaker according to thepresentinvention may be easily manufactured by using a molded cylindermember of insulating material and a simple form and inserting at oneends the insulated conductors of a fixed length, which are connectabl'eatthe other ends, for example, to the connection lead'wires of anotherelectric machinery and are manufactured separately, into the holes boredat the corresponding positions of the side wall of said main insulatingcylinder. 2

' Other objects and advantages of the invention will become apparentfrom the following description taken in connection with the accompanyingdrawings. Further, the same reference numeral in the drawings is used toindicate the same part and the reference numeral put with a dashindicates the similar part to that indicated. by the numeral without adash.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial vertical sectionalview of a preferred embodiment of the solid material insulated andsmall-sized breaker according to' the present invention;

FIGS. 2 and 3 are respectively partial sectional viewsof the twodifferent insulated conductors for the dis connecting section preferredfor the breaker shown in FIGS. 5 and 6 are respectivelypartial sectionalviews of another embodiments of insulated conductor for thedisconnecting section shown in FIGS. 2 and3 attached to the housing bysuitable fixing means;

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1, there is showna small-sized and solid material insulated breaker or interrupter, morespecially a vacuum breaker according to the present invention. Thisbreaker includes insulated electrical conductors 12, 14 and a housing16. v

As shown in FIG. 2, the insulated electrical conductors or leads 12, 16are respectively formed with an elongated electric conductor 18 of afixed length and a circumferential layer 20. Both endsof said electricconductor 18 are respectively exposed for connecting to another electricconductors. The circumferential layer 20 is provided with a cylindricalsolid insulator 22 of an epoxy resin, two capacitor cones 28,30concentrically arranged therein and an electrically groundingcylindrical layer of greater diameter. This circumferential layer may beformed by winding a paper and the like to a suitable thickness around anelongated electric conductor 18, disposing cylindrical electricconductor layers 24a, 24b, 24c, 24d and 26a, 26b, 26c, 26d, which haverespectively diameters growing consecutively in this order,concentrically near both ends of the elongated conductor respectively soas to form two capacitor cones 28, 30 with the top points of the conessituated near both ends respectivelyof the elongated conductor,providing as a grounding "layer a cylindrical electrical conductorhaving a lengthalmost equalto the axial distance between the supposedbottom faces of the two cones and having the external diameter a fixeddimension smaller than that of the circumferential layer 20,impregnating the intermediate product thusobtained with insulatingmaterial such as epoxy resin, and depositing the insulating materialaround the cylindrical grounding layer to a fixed thickness. Theexternal circumference of said circumferential layer 20 is provided withscrews and the external circumferential of the grounding layer 32 issuch that it exist radially inside the core diameter of said screws-FIG. 3 is another modification of the insulated conductor which isconnected at one end to an electrical lead of another device at thedisconnecting section (not shown). In the FIG. 3, there is shown amolded product including concentrical shield rings 34, 36 formed withthe electric conductor material electrically connected to both ends ofthe grounding layer 32' instead of the capacitor cones shown in FIG. 2.l

In FIG. 4, there is shown a main molded cylinder 36 of insulatingmaterial used for the housing 16 of the breaker in FIG. 1. This maincylinder includes a cylindrical electric conductor layer 38 as itsgrounding layer buried in the wall of the cylinder 36 instead ofproviding a grounding layer on the outer surface thereof. F ur-..

ther for the purpose of passing the insulated conductor shown in FIGS. 3or 4, holes or openings 40, 42 are formed separating from each otherlongitudinally at a fixed distance in the wall of the cylinder. On theexternal circumferences of both ends of the main cylinder 36, screws areprovided for receiving cylindrical sup porting members (described later)including also complementary screws formed on the inside surfacesthereof respectively. Accordingly, the external surface of the conductorlayer 38 must be placed inside the core diameter of the screws providedupon the external surface of the main cylinder 36. Otherwise, theconductor layer 38 will be cut off at places corresponding to thebottoms of screws which will be provided and the corona discharge willoccur when used. For manufacturing the main cylinder 36 having theconductor layer 38 inside the wall thereof, it is preferable that theconductor layer 38 should be rolled around the external circumference ofmolded cylinder of insulating material or around a externalcircumference of the cylinder produced bywinding a paper and the like toa fixed thickness around a core rod having a desired external diameterand 'then removing the core rod from the resultant article, that a paperand the like should be wound around the conductor layer thus formed, andthat the intermediate product thus obtained should be impregnated withinsulating epoxy resin.

Referring once, more to FIG. 1, both cylindrical supporting members 44and 46 of metal material, on the inside surfaces of which screws areformed, are

screwed on the external'surface of the main cylinder 36 at predeterminedheights respectively. Of course, screws are formed on the externalsurface of the cylinder 36. In the side wall of each supporting member44, 46, openings 48, 50 are provided and aligned with the openings 40,42, respectively, in the main insulating cylinder 36. Then, through theopenings 40, 42 of said main insulating cylinder 36 as well as throughthe openings 48, 50 of said supporting members 44, 46, both insulatedconductors 12, 14, respectively, are inserted in common.

Further, both metal fittings 52, 54 are fitted respectively on the screwportions formed around the external circumferences of the insulatedconductor 12, 14 by the screws provided on the inside surfaces of thecylindrical portions 52a, 54a of the fittings 52, 54. The left sidesurfaces of the flange portions radially externally extending from theleft ends (viewed in FIG. 1) of each cylindrical portions 52a, 54a ofsaid fittings 52, 54 are fonned in a supplemental shape for thesupporting members 44, 46 and firmly attached by suitable fixing meanssuch as screws 56, 58 to the external side surfaces of the supportingmembers. Between-each of the screwed inner wall surface of thecylindrical portions 52a, 54a of the fittings 52, 54 and each of screwportions of the outer surfaces of the insulated conductors l2, l4,adhesive including such as a resin material and the like is filled up,and thus the fitting 52 and the insulated conductor l2 as well as thefitting 54 and the insulated conductor 14 are respectively connectedmechanically fixedly in a body. Consequently, when a liquid or gasinsulation medium (described later) is filled up into the housing 16, itdoes not leak out from between each fitting and insulated conductor,thus a perfect liquid-tight and gas tight structure is provided.Numerals 60 and 62 indicate respectively O-rings inserted between thesupport member 44 and the fitting 52 as well as between the supportmember 46 and the fitting 54, and they prevent the leak out of theliquid insulating medium filled inside the housing 16 from between eachsupport member' and each fitting.

Inside the main cylinder 36, a vacuum breaker unit 64 is inserted. Thisunit is shown as including two cylindrical glassy containers 66, 68, aring-shaped electric conductor portion 69 connecting the containers toeach other, and electrically conductive plates or flanges 70, 72provided at remote ends of the containers 66, 68. However, of course,within the containers 66, 68, fixed and movable contacts are provided.The upper end 73 of the electric conductor connected to said'fixedcontact passes throught the upper conducting plate and appears on theupper portion of the unit 64. It is inserted through conductiveconnecting ring 76 intoa concave provided in the lower part of asubstantially trapezoid-shaped, electrically conducting medium 74. n

The right side surface (viewed in FIG. 1) of the trapezoid-shapedmedium. 74 includes a concave wherein the exposed left end (in FIG. 1)of the insulated conductor 12 for the disconnecting section is insertedthrough the ring-shaped contact 78. On the upper surhaving a somewhatsmall diameter as compared with that of the main insulating cylinder 36,and it is supported on the upper surface of the main insulating cylinder36. As is clearly shown in FIG. 1, the upper surface of the supportmember 44 fitted on the upper circumferential portion of said maininsulating-cylinder 36 is placed at the same level as the upper surfaceof the flange portion 80b of'the V-shaped supporting element 80. Forsealing up the upper opening of the main insulating cylinder 36, thereis provided a cap 82 thereon, wherein the lower circumferential surfaceof the cap is contacted on the upper surfaces of the support member 44and the supporting element 80 respectively and is attached by suitablemeans such as ascrew 84 and the like to the upper surface of thesupporting member 44. Between the upper surface of the main insulatingcylinder 36 and the lower surface of the flange portion 80b of the upperportion of the V-shaped supporting element 8,0 as well'as between theupper surface of the flange portion 80b of the V-shaped supportingelement 80 and the lower surface of the circumferential portion of thecap 82, there are provided O-ring86, 88, respectively, for the liquidand gas-tight purpose.

At the lower surface of the lower conducting plate 72 of electricallyconducting material for the breaker unit 64, a lower, electricallyconducting medium 90 having a symmetrical section as compared with theupper medium 74 is provided integral with the electrically conductingplate 72, and it is supported by an insulating support cylindricalmember 92. On the outer circumference of the lower portion of the maininsulating cylinder 36, a cylindrical 'supportingmember 94 is fitted bya screw formed on the inside surface of the supporting member engagingthe screwprovided on the outer circumference of the lower portion of themain insulating cylinder 36. The supporting member 94 is secured to thebase plate 98 by a fitting means such as a screw member 96 and it isused as a part for attaching the breaker as a whole to the base plate98.

At the upper center of the lower medium 90, there is provided a concaveand at the central portion of the medium 90, a vertical hole 100 isformed communicating with the concave or depression of the medium.Inside the hole 100, a movable lead member 102 connected to the movablecontact (not shown in FIG. 1) of the breaker unit 64 is inserted. Anelectrically conductive ringed contact member 103 for connecting themovable lead rod 102 and the lower trapezoidal medium 90 to each otheris inserted into the depression with the rod 102 threaded therein. Thelower part of the movable lead member 102 is pivoted at the upper end ofa bar 104 of electrically insulating material. The lower end of theinsulating bar 104 is pivoted at the tip 1100 of a crank 110 which ispivotable around an axis 108. Accordingly, by the swinging motion of thecrank, the movable lead 102 may reciprocate to connect and disconnectthe movable contact secured on the lead 102 to and from, respectively,the fixed contact inside the breaker unit. Numeral 112 is a casing ofthe crank and it is attached to the lower surface of the base plate 98.

At the right side surface (in FIG. 1) of the lower trapezoidal medium90, there isprovided a concave or depression in which is received anelectrically conductive ringed contact 114, in which, in turn, isinserted one exposed end of an insulated electrical conductor 14,similar to the insulated conductor 12, passing through the opening 42(FIG. 4) of the main insulating cylinder 36. Accordingly, when the fixedcontact and the movable contact in the breaker unit 64 are contacted, anelectric passage is formed passing through the electric conductor 18 ofthe insulated conductor 12, the upper trapezoidal medium 74, the fixedand movable contacts of the-breaker unit 64, the lower trapezoidalmedium 90 and the conductor 18 of the lower insulated conductor 14.

In the space between the cylindrical supporting members 44, 46 and themain insulating cylinder 36, adhesive such as an epoxy resin is filledand solidified and thus both screwed portions of the members 44, 46 andthe cylinder 36 are fastened to each other in a gas and liquid-tightcondition. The supporting members 46, 94 may beformed as structuallyintegral with each other, but when they are manufactured separately asin FIG. 1, it is convenient that the supporting member 46 may bedisposed in place away from the member 44 according to the length of thebreaker unit inserted into the main insulating cylinder 36. As will beclearly understood from the above descriptions, (the housing 16 of thebreaker is formed with the base 98, the main insulating cylinder 36 andthe cap 82. Numeral 116 is a liquid insulating medium such as anelectrically insulating oil inserted into the housing. Numeral 118 is an0-ring inserted between the supporting member 94 and the plate 98 is asupporting box 120 with the base plate fixed thereon by a screw member122.

Now, reference is made to the voltage shares taken by the structuralelements, respectively, of the breaker according to the presentinvention. Firstly, attention is directed to the insulated electricconductors l2 and 14. Obviously, as seen in FIG. 1, the insulatedconductors l2, 14 are, at the left portions thereof inserted into theliquid insulating medium 116 inside the housing 16, and connected at theleft exposed ends thereof to the upper and lower trapezoidal mediums 74,90 through the corresponding ringed contacts 78, 114, respectively.Further, the left end portions of the soild circumferential layers 20,20 for the upper and lower insulated conductors ,12, 14 are at the outersurfaces thereof, respectively, contacted with the liquid insulatingmedium 116 in the housing 36. Now, assume that the right half portionsof the conductors l2, 14 are inserted in liquid insulating medium in thecasings of anvoltage in respect to ground is applied to the insulatedconductor 12 through the corresponding disconnecting switch from asource of power. The insulated conductor 12 has a pair of capacitorcones or shield rings as shown in FIGS. 2 or 3 embedded in thecircumferential layer or 20', respectively, so that a predetermineddielectric strength may be obtained along the external circumference ofthe circumferential layer 20 of the insulated conductor 12 between theleft exposed conductor portion of the insulated conductor 12 and the endedge 38a of the grounding layer 38 of the main insulating cylinder 36.Accordingly, the creeping dielectric strength of the insulated conductor12 portion in the housing 16 is sufficiently kept. This applies also tothe lower insulated conductor 14. i i

Then, the creeping dielectric strength is referred in connection withthe opening 40 of the main insulating cylinder 36. As shown in FIG. 1,in the wall of the main insulating cylinder 36, the grounding layer 38is concentrically provided. Accordingly, a predetermined dielectricstrength is required, for example between the edge 38a of the groundinglayer 38 exposed at the opening 40 of the main insulating cylinder 36and the right lower edge 74a of the upper trapezoidal medium 74 as wellas the'right flange portion of the upper conductive plate 70 for thebreaker unit 64 respectively. Apparently, the exposed edge 38 is atground potential, andthe upper trapezoidal medium 74, the flange portionof the conductive plate 70 for the breaker unit 64 and the ring-shapedconductive portion 69 connecting the glassy containers 66, 68 to eachother are at a predetermined high voltage level. According|y,'when aflash over will occur, the passages thereof are [3,, B and 63, shown ina broken line, whichpass from respectively the lower right end portion74a of the upper trapezoidal medium 74, the right flange portion oftheconductive plate 70 and the right flange portion of the intermediateconductive portion 69, through the liquid insulating medium 116 alongthe opening surface of the main insulating cylinder 36, to the exposededge 38a of the grounding layer 38. These also apply to the lowerinsulated conductor 14. In this case, if the distance of the liquidinsulating medium between either of the upper trapezoidal medium 74 andthe voltage charged conductive portions (namely the conductive plate 70and the conductive portion 69) and the exposed edge 38a of the groundinglayer, as well as the respective contours of the charged portions 70, 69and the upper trapezoidal medium 74 are suitably selected, a solid statematerial insulated and small-sized breaker having a better dielectricstrength may be manufactured.

In the present embodiment, the liquid insulating medium 116 is filled upinside the main insulating cylinder, but the insulating medium is notlimited to the liquid one, a gas insulating medium such as SF, (sulfurhexafluoride) gas may be used.

Further, in this embodiment, the fittings 52, 54 threaded upon theinsulated conductor l2, 14 are attached to the cylindrical supportingmembers 44, 46 by fitting means such as bolts 56, 58, but the fittingway is not limited to the just-mentioned one. For example, as shown inFIG. 5, the supporting member 44' or 46' may be provided with a screwhole directly therein and fitted in place on the exterior circumferenceof the main insulating cylinder 36, and then the insulated conductor 12or 14 may be screwed directly into the screw hole instead of using thefitting 52 or 54 shown in FIG.

1. Moreover, as shown in FIG. 6, it goes without saying that theinsulated conductor 12 or 14 may be screwed directly into a screw holebored in the main insulating cylinder 36.

As described above, as the main insulating cylinder 36 and the insulatedconductor 12, 14 according to the breaker of the present invention areof a simple cylindrical form, the molding price is moderate. Further. ifthe breaker according to the present invention is requested to change infitting or mounting conditions without changing the electric ratingthereof, the insulated conductors '12, 14 can only be requested tochange in length instead of changing the form of the main cylinder 16.Accordingly, the mold types can be limited to a small number, andvarious breakers may be economically manufactured if in a small amount.Further, on the other hand, the opening for attaching an insulatedconductor may be easily formed in the side wall of the main cylinder ata certain position decided according to the using conditions, and on theother hand, an insulated conductor may be easily produced as a long orshort one'according to the fitting conditions such as the fittingdimentions, for example, length to a power-board or other electricmachines. Therefore, the breaker may be manufactured generallyeconomically according to the present invention.

While the invention has been particulary described with reference topreferred embodiment, changes and modifications may be easily possibleto those skilled in the art. But it is intended to cover all the changesand modifications which do not constitute departures from the spirit andscope'ofthe invention.

What we claim is:

l. A solid state material insulated breaker of a small size comprising amain cylinder of electrically insulating solid state material and sealedat the first and second ends thereof, said main cylinder'having twoopenings longitudinally spaced from each other in the wall thereof, abreaker unit enclosed in said main cylinder and having a movable and afixed contacts therein, means for fixing said breaker unit in said maincylinder, two insulated electric conductors inserted through said twoopenings of said main cylinder, one ends of which conductors areelectrically connected respectively to said fixed and movable contactsof said breaker unit, each insulated conductor including an elongated,electric conductor and a solid insulating material layer formed aroundthereof in a fixed thickness, means for attaching said insulatedconductors, respectively, to said main cylinder and a insulatingmaterial filled into the space between said sealed main cylinder andsaid breaker enclosed therein.

2. A solid state material insulated breaker of a small I size as claimedin claim' 1, wherein said solid insulating material layer of eachinsulated conductor includes concentrically a cylindrical electricallyconductive layer and two conductive rings electrically connected to bothends of said conductor.

3. A solid state material insulated breaker of a small size as claimedin claim 1, wherein said solid insulating material layer includesconcentrically a cylindrical electrically conductive and two capacitorcones arranged near both ends of said solid state insulating materiallayer, the top point of each cone being disposed near the outer end ofsaid insulating material layer, each said capacitor cone consisting of aplurality of cylindrical electric conductors each having almost samlength and different radius.

I 4. A solid state material insulated breaker of a small size as claimedin claim 2, wherein said main cylinder includes concentrically acylindrical, electrically conductive layer in the side wall thereof.

5. A solid state material insulated breaker of a small size asclaimed-in claim 3, wherein said main cylinder includes a cylindrical,electrically conductive layer in the side wall thereof.

6. A solidstate material insulated breaker of a small size as claimed inclaim 1, wherein at least one of said means for attaching said insulatedconductors to said main cylinder including a cylindrical supportingmember concentrically attached to theexternal circumference of said maincylinder and a fitting member'fitted over a corresponding insulatedconductor and attached to said supporting member, said fitting memberconsisting of a cylindrical portion concentrically applied on theexternal circumference of said corresponding insulated conductor and aflange portion attached to the external circumference of said supportingmember.

7. A solid state material insulated breaker ofa small size as claimed inclaim 6, wherein 'said corresponding insulated conductor and thecylindrical portion of said fitting member attached concentrically onthe external circumference of said corresponding insulatedconductor areconnected to each other by screws provided on their adjoining surfaces,respectively.

8. A solid state material insulated breaker of a small size as claimedin claim 7, wherein adhesive is filled up and solidified in the spacebetween said corresponding insulated conductor and said fitting memberapplied on the outer circumference thereof. i

9. A solid state material insulated breaker of a small size as claimedin claim 1, wherein the connection between said main cylinder and saidsupporting member fitted concentrically on the external circumference ofsaid main cylinder is performed by screws formed on the adjoiningsurfaces of said supportingmember and saidmain cylinder.

10. A solid state material insulated breaker of a small size as claimedin claim 9, wherein adhesive is filled up in the space between said maincylinder and said supporting member. a

11. A solid state material insulated breaker of a small size as claimedin claim 1, further including a base plate and a cylindrical supportingmember for mounting said main cylinder on said base plate, the lastmentioned supporting member being screwed concentrically on the externalcircumference of the second end of said main cylinder.

12. A solid state material-insulated breaker of a small size as claimedin claim 11, wherein said insulated conductor attaching means is formedintegral with said supporting member for mounting said main cylindersaid base plate.

13. A solid state materialinsulated breaker of a small size comprising amain insulating cylinder having two openings axially spaced from eachother therein and sealed at its upper and lower ends, a breaker unitenclosed in said main insulating cylinder and having movable and fixedcontacts therein, means for supporting said breaker unit, two solidstate material insulated electric conductors inserted into said twoopenings of said main insulating cylinder and electrically connected tothe movable and fixed contacts of said breaker unit,

taching including a cylindrical supporting member attachedconcentrically to the external circumference of said main insulatingcylinder in a liquid-and gas-tight condition, said supporting memberhaving a screwed hole in theside wall thereof, said screwed hole, whenin place, being capable of aligning with the hole provided in the sidewall of said main insulating cylinder, said insulated conductor beinginserted through said two holes aligned with each other in a liquid-andgastight condition and electrically connected to said fixed and movablecontacts of said breaker unit.

14. A solid state material insulated breaker of a small size as claimedin claim 13, wherein a cylindrical, electrically conductive layer isconcentrically formed in the side wall of the main insulating cylinder.

15. A solid state material insulated breaker of a small size as claimedin claim 1, wherein a screw is formed on the internal surface of atleast one of said openings provided in the side wall of said maininsulating cylinder, and a screw complementary to said just mentionedscrew is formed on the external circumference of the solid statematerial around each solid state material insulated conductor which isinserted into said screwed opening of said main insulating cylinder.

16. A solid state material insulated breaker of a small size, as claimedin claim l3, wherein an upper end of said main insulating cylinder issealed by a cap, an upper-supporting means for said breaker unitis'provided over said breakerunit and provided'with a flange portioncontacted to the upper end surface of said main insulating cylinder,said flange portion being supported respectively by the upper endsurface of said main insulating cylinder and the lower circumferentialsurface of said cap, a lower supportingmeans for said breaker unitincluding a small insulating cylinder provided below the breaker unitand further a base is provided for supporting said small insulatingcylinder.

l7 A solid state 'r naterial insulated breaker of a small size asclaimed in claim 16, further including an upper electrically conductivemedium provided between said 'upper supporting means and said breakerunit for electrically connecting said fixed contact of said breaker witha corresponding insulated electrical conductor therefor, a lowerelectrically conductive medium provided between said lower supportingmeans and said breaker unit for electrically connecting said movablecontact of said breaker unit with a corresponding insulated electricalconductor therefor, said lower medium having a vertical hole at thecenter thereof, a movable lead of electrically conductive material andconnected with said movable contact of said breaker being supported soas to reciprocate in said vartical hole, .and mean for driving saidmovable lead.

18. A solid state material insulated breaker of a small size as claimedin claim 17, said means for driving said movable lead includes a crankmeans swingable around a fixed pivot point.

19. A solid state material insulated breaker of a small size comprisingamain insulating cylinder sealed at the ,upper and lower ends thereof, abreaker unit enclosed rial, said conductors passing through the wall ofsaid;

main insulating cylinder at two axially spaced points 20. A solid statematerial insulated breaker as claimed in claim 19, wherein saidinsulating medium includes a gas material.

1. A solid state material insulated breaker of a small size comprising amain cylinder of electrically insulating solid state material and sealedat the first and second ends thereof, said main cylinder having twoopenings longitudinally spaced from each other in the wall thereof, abreaker unit enclosed in said main cylinder and having a movable and afixed contacts therein, means for fixing said breaker unit in said maincylinder, two insulated electric conductors inserted through said twoopenings of said main cylinder, one ends of which conductors areelectrically connected respectively to said fixed and movable contactsof said breaker unit, each insulated conductor including an elongated,electric conductor and a solid insulating material layer formed aroundthereof in a fixed thickness, means for attaching said insulatedconductors, respectively, to said main cylinder and a insulatingmaterial filled into the space between said sealed main cylinder andsaid breaker enclosed therein.
 2. A solid state material insulatedbreaker of a small size as claimed in claim 1, wherein said soliDinsulating material layer of each insulated conductor includesconcentrically a cylindrical electrically conductive layer and twoconductive rings electrically connected to both ends of said conductor.3. A solid state material insulated breaker of a small size as claimedin claim 1, wherein said solid insulating material layer includesconcentrically a cylindrical electrically conductive and two capacitorcones arranged near both ends of said solid state insulating materiallayer, the top point of each cone being disposed near the outer end ofsaid insulating material layer, each said capacitor cone consisting of aplurality of cylindrical electric conductors each having almost samelength and different radius.
 4. A solid state material insulated breakerof a small size as claimed in claim 2, wherein said main cylinderincludes concentrically a cylindrical, electrically conductive layer inthe side wall thereof.
 5. A solid state material insulated breaker of asmall size as claimed in claim 3, wherein said main cylinder includes acylindrical, electrically conductive layer in the side wall thereof. 6.A solid state material insulated breaker of a small size as claimed inclaim 1, wherein at least one of said means for attaching said insulatedconductors to said main cylinder including a cylindrical supportingmember concentrically attached to the external circumference of saidmain cylinder and a fitting member fitted over a corresponding insulatedconductor and attached to said supporting member, said fitting memberconsisting of a cylindrical portion concentrically applied on theexternal circumference of said corresponding insulated conductor and aflange portion attached to the external circumference of said supportingmember.
 7. A solid state material insulated breaker of a small size asclaimed in claim 6, wherein said corresponding insulated conductor andthe cylindrical portion of said fitting member attached concentricallyon the external circumference of said corresponding insulated conductorare connected to each other by screws provided on their adjoiningsurfaces, respectively.
 8. A solid state material insulated breaker of asmall size as claimed in claim 7, wherein adhesive is filled up andsolidified in the space between said corresponding insulated conductorand said fitting member applied on the outer circumference thereof.
 9. Asolid state material insulated breaker of a small size as claimed inclaim 1, wherein the connection between said main cylinder and saidsupporting member fitted concentrically on the external circumference ofsaid main cylinder is performed by screws formed on the adjoiningsurfaces of said supporting member and said main cylinder.
 10. A solidstate material insulated breaker of a small size as claimed in claim 9,wherein adhesive is filled up in the space between said main cylinderand said supporting member.
 11. A solid state material insulated breakerof a small size as claimed in claim 1, further including a base plateand a cylindrical supporting member for mounting said main cylinder onsaid base plate, the last mentioned supporting member being screwedconcentrically on the external circumference of the second end of saidmain cylinder.
 12. A solid state material insulated breaker of a smallsize as claimed in claim 11, wherein said insulated conductor attachingmeans is formed integral with said supporting member for mounting saidmain cylinder on said base plate.
 13. A solid state material insulatedbreaker of a small size comprising a main insulating cylinder having twoopenings axially spaced from each other therein and sealed at its upperand lower ends, a breaker unit enclosed in said main insulating cylinderand having movable and fixed contacts therein, means for supporting saidbreaker unit, two solid state material insulated electric conductorsinserted into said two openings of said main insulating cylinder andelectrically connected to the movable and fixed contacts of said breAkerunit, respectively and means for attaching said insulated conductors tosaid main insulating cylinder, respectively, at least one of said lastmentioned means for attaching including a cylindrical supporting memberattached concentrically to the external circumference of said maininsulating cylinder in a liquid-and gas-tight condition, said supportingmember having a screwed hole in the side wall thereof, said screwedhole, when in place, being capable of aligning with the hole provided inthe side wall of said main insulating cylinder, said insulated conductorbeing inserted through said two holes aligned with each other in aliquid-and gas-tight condition and electrically connected to said fixedand movable contacts of said breaker unit.
 14. A solid state materialinsulated breaker of a small size as claimed in claim 13, wherein acylindrical, electrically conductive layer is concentrically formed inthe side wall of the main insulating cylinder.
 15. A solid statematerial insulated breaker of a small size as claimed in claim 1,wherein a screw is formed on the internal surface of at least one ofsaid openings provided in the side wall of said main insulatingcylinder, and a screw complementary to said just mentioned screw isformed on the external circumference of the solid state material aroundeach solid state material insulated conductor which is inserted intosaid screwed opening of said main insulating cylinder.
 16. A solid statematerial insulated breaker of a small size, as claimed in claim 13,wherein an upper end of said main insulating cylinder is sealed by acap, an upper supporting means for said breaker unit is provided oversaid breaker unit and provided with a flange portion contacted to theupper end surface of said main insulating cylinder, said flange portionbeing supported respectively by the upper end surface of said maininsulating cylinder and the lower circumferential surface of said cap, alower supporting means for said breaker unit including a smallinsulating cylinder provided below the breaker unit and further a baseis provided for supporting said small insulating cylinder.
 17. A solidstate material insulated breaker of a small size as claimed in claim 16,further including an upper electrically conductive medium providedbetween said upper supporting means and said breaker unit forelectrically connecting said fixed contact of said breaker with acorresponding insulated electrical conductor therefor, a lowerelectrically conductive medium provided between said lower supportingmeans and said breaker unit for electrically connecting said movablecontact of said breaker unit with a corresponding insulated electricalconductor therefor, said lower medium having a vertical hole at thecenter thereof, a movable lead of electrically conductive material andconnected with said movable contact of said breaker being supported soas to reciprocate in said vartical hole, and mean for driving saidmovable lead.
 18. A solid state material insulated breaker of a smallsize as claimed in claim 17, said means for driving said movable leadincludes a crank means swingable around a fixed pivot point.
 19. A solidstate material insulated breaker of a small size comprising a maininsulating cylinder sealed at the upper and lower ends thereof, abreaker unit enclosed in said main insulating cylinder, two electricalconductors insulated around with a solid state insulating material, saidconductors passing through the wall of said main insulating cylinder attwo axially spaced points thereon and connected to the correspondingpoints of said breaker unit, and an insulating medium filling up thespace between said main sealed insulating cylinder and said breaker unittherein, said insulating medium including liquid material.
 20. A solidstate material insulated breaker as claimed in claim 19, wherein saidinsulating medium includes a gas material.